A British Phonographic Industry spokesman said he did not believe the chart would rival "physical formats" such as CD singles.

"I think it's going to be a shot in the arm for music generally," he said. "This is not a competitor to the singles chart. It is a different kind of thing entirely.

'New window'

"It is reacting to a demand that hasn't been satisfied. It's going to give people a new window," he said.

"The launch of the UK's Official Download Chart shows the revolution is
here," said OCC charts director Omar Maskatiya said.

"The Official UK Download Chart marks the most significant development in the charts since the advent of the compact disc 20 years ago."

The music industry is hoping the new chart will boost the demand for singles - CD single sales fell by more than 32% in the last 12 months.

Test chart

A first test chart is published this week and is topped by the Pixies' Bam Thwok - a new track made available exclusively via Apple iTunes.

The Pixies' Bam Thwok heads the first test chart

Other sites that will be included are OD2, Metacharge, 7 Digital Media and Playlouder.

Mycokemusic.com was the first site to confirm its involvement. In six months it has attracted 2.5 million visitors, with Left Outside Alone by US soul singer Anastacia emerging as the most-downloaded song on the service.

"Accessing music through legal downloading is a major part of the future of music and should be represented with its own chart," BPI chairman Peter Jamieson said.

"The launch of the Official Download Chart this September demonstrates the growing maturity of the legal download market in the UK," he said.

The International Federation of the Phonographic Industry (IFPI) chairman Jay Berman also welcomed it.

"The creation of the UK chart shows that legal, high quality and easy to use music download sites are a hit with consumers and look set to be a fast-growing part of the music buying experience in the future."